Why do people cluster together in neighbourhoods? How do Internet communities spring up from nowhere? Why is a brain conscious even though no single neuron is? What causes a media frenzy?
The answer, as Steven Johnson's groundbreaking book shows, is emergence: change that occurs from the bottom up. When enough individual elements interact and organise themselves, the result is collective intelligence - even though no one is in charge. It is a phenomenon that exists at every level of experience, and will revolutionise the way we see the world.